/* dhcpd.c DHCP Server Daemon. */ /* * Copyright (c) 1995, 1996, 1997 The Internet Software Consortium. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of The Internet Software Consortium nor the names * of its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * This software has been written for the Internet Software Consortium * by Ted Lemon in cooperation with Vixie * Enterprises. To learn more about the Internet Software Consortium, * see ``http://www.vix.com/isc''. To learn more about Vixie * Enterprises, see ``http://www.vix.com''. */ #ifndef lint static char ocopyright[] = "$Id: dhcpd.c,v 1.1.1.4 1997/06/08 04:55:23 mellon Exp $ Copyright 1995, 1996 The Internet Software Consortium."; #endif static char copyright[] = "Copyright 1995, 1996 The Internet Software Consortium."; static char arr [] = "All rights reserved."; static char message [] = "Internet Software Consortium DHCPD $Name: $"; #include "dhcpd.h" static void usage PROTO ((void)); TIME cur_time; struct group root_group; struct iaddr server_identifier; int server_identifier_matched; #ifdef USE_FALLBACK struct interface_info fallback_interface; #endif u_int16_t local_port; u_int16_t remote_port; int log_priority; #ifdef DEBUG int log_perror = -1; #else int log_perror = 1; #endif char *path_dhcpd_conf = _PATH_DHCPD_CONF; char *path_dhcpd_db = _PATH_DHCPD_DB; char *path_dhcpd_pid = _PATH_DHCPD_PID; int main (argc, argv, envp) int argc; char **argv, **envp; { int i, status; struct servent *ent; char *s; int cftest = 0; #ifndef DEBUG int pidfilewritten = 0; int pid; char pbuf [20]; int daemon = 1; #endif /* Initially, log errors to stderr as well as to syslogd. */ #ifdef SYSLOG_4_2 openlog ("dhcpd", LOG_NDELAY); log_priority = DHCPD_LOG_FACILITY; #else openlog ("dhcpd", LOG_NDELAY, DHCPD_LOG_FACILITY); #endif #ifndef DEBUG #ifndef SYSLOG_4_2 #ifndef __CYGWIN32__ /* XXX */ setlogmask (LOG_UPTO (LOG_INFO)); #endif #endif #endif note (message); note (copyright); note (arr); for (i = 1; i < argc; i++) { if (!strcmp (argv [i], "-p")) { if (++i == argc) usage (); for (s = argv [i]; *s; s++) if (!isdigit (*s)) error ("%s: not a valid UDP port", argv [i]); status = atoi (argv [i]); if (status < 1 || status > 65535) error ("%s: not a valid UDP port", argv [i]); local_port = htons (status); debug ("binding to user-specified port %d", ntohs (local_port)); } else if (!strcmp (argv [i], "-f")) { #ifndef DEBUG daemon = 0; #endif } else if (!strcmp (argv [i], "-d")) { #ifndef DEBUG daemon = 0; #endif log_perror = -1; } else if (!strcmp (argv [i], "-cf")) { if (++i == argc) usage (); path_dhcpd_conf = argv [i]; } else if (!strcmp (argv [i], "-lf")) { if (++i == argc) usage (); path_dhcpd_db = argv [i]; } else if (!strcmp (argv [i], "-t")) { /* test configurations only */ #ifndef DEBUG daemon = 0; #endif cftest = 1; log_perror = -1; } else if (argv [i][0] == '-') { usage (); } else { struct interface_info *tmp = ((struct interface_info *) dmalloc (sizeof *tmp, "get_interface_list")); if (!tmp) error ("Insufficient memory to %s %s", "record interface", argv [i]); memset (tmp, 0, sizeof *tmp); strcpy (tmp -> name, argv [i]); tmp -> next = interfaces; tmp -> flags = INTERFACE_REQUESTED; interfaces = tmp; } } #ifndef DEBUG if (daemon) { /* First part of becoming a daemon... */ if ((pid = fork ()) < 0) error ("Can't fork daemon: %m"); else if (pid) exit (0); } /* Read previous pid file. */ if ((i = open (path_dhcpd_pid, O_RDONLY)) >= 0) { status = read (i, pbuf, (sizeof pbuf) - 1); close (i); pbuf [status] = 0; pid = atoi (pbuf); /* If the previous server process is not still running, write a new pid file immediately. */ if (pid && kill (pid, 0) < 0) { unlink (path_dhcpd_pid); if ((i = open (path_dhcpd_pid, O_WRONLY | O_CREAT, 0640)) >= 0) { sprintf (pbuf, "%d\n", (int)getpid ()); write (i, pbuf, strlen (pbuf)); close (i); pidfilewritten = 1; } } } #endif /* !DEBUG */ /* Default to the DHCP/BOOTP port. */ if (!local_port) { ent = getservbyname ("dhcp", "udp"); if (!ent) local_port = htons (67); else local_port = ent -> s_port; #ifndef __CYGWIN32__ /* XXX */ endservent (); #endif } remote_port = htons (ntohs (local_port) + 1); /* Get the current time... */ GET_TIME (&cur_time); /* Initialize DNS support... */ dns_startup (); /* Read the dhcpd.conf file... */ if (!readconf ()) error ("Configuration file errors encountered -- exiting"); /* test option should cause an early exit */ if (cftest) exit(0); /* Start up the database... */ db_startup (); /* Discover all the network interfaces and initialize them. */ discover_interfaces (1); /* Initialize icmp support... */ icmp_startup (1, lease_pinged); #ifndef DEBUG /* If we were requested to log to stdout on the command line, keep doing so; otherwise, stop. */ if (log_perror == -1) log_perror = 1; else log_perror = 0; if (daemon) { /* Become session leader and get pid... */ close (0); close (1); close (2); pid = setsid (); } /* If we didn't write the pid file earlier because we found a process running the logged pid, but we made it to here, meaning nothing is listening on the bootp port, then write the pid file out - what's in it now is bogus anyway. */ if (!pidfilewritten) { unlink (path_dhcpd_pid); if ((i = open (path_dhcpd_pid, O_WRONLY | O_CREAT, 0640)) >= 0) { sprintf (pbuf, "%d\n", (int)getpid ()); write (i, pbuf, strlen (pbuf)); close (i); pidfilewritten = 1; } } #endif /* !DEBUG */ /* Set up the bootp packet handler... */ bootp_packet_handler = do_packet; /* Receive packets and dispatch them... */ dispatch (); /* Not reached */ return 0; } /* Print usage message. */ static void usage () { error ("Usage: dhcpd [-p ] [-d] [-f] [-cf config-file]%s", "\n [-lf lease-file] [if0 [...ifN]]"); } void cleanup () { } void lease_pinged (from, packet, length) struct iaddr from; u_int8_t *packet; int length; { struct lease *lp; /* Don't try to look up a pinged lease if we aren't trying to ping one - otherwise somebody could easily make us churn by just forging repeated ICMP EchoReply packets for us to look up. */ if (!outstanding_pings) return; lp = find_lease_by_ip_addr (from); if (!lp) { note ("unexpected ICMP Echo Reply from %s", piaddr (from)); return; } if (!lp -> state) { warn ("ICMP Echo Reply for %s arrived late or is spurious.\n", piaddr (from)); return; } /* At this point it looks like we pinged a lease and got a response, which shouldn't have happened. */ free_lease_state (lp -> state, "lease_pinged"); lp -> state = (struct lease_state *)0; abandon_lease (lp, "pinged before offer"); cancel_timeout (lease_ping_timeout, lp); --outstanding_pings; } void lease_ping_timeout (vlp) void *vlp; { struct lease *lp = vlp; --outstanding_pings; dhcp_reply (lp); }